Apparatus for drawing hard-metal tubes.



No. 880,563. PATENTED MAR. 3, 1908.

B. F. MOTEAR.

APPARATUS FOR DRAWING HARD METAL TUBES.

APPLICATION FILED MAB.7.1902.

3 SHEETS-SHEET 2.

masses,- MM zfwzm ATTORNEYS.

No. 880,563. A PATENTBD MAR.3,1908. B. F. MoTEAR.

APPARATUS FOR DRAWING HARD METAL TUBES.

AP LIOAT NIILED H B. .1902.

P I0 A 7 3 SHEETS-SHEET 3.

i Fi .5.

INVENTOR. gin/38580; w film) 37,; M @6.,,\

ATTORNEYS T $TATES PATENT OFFICE. j BALFOIU'R FIRDASEJR ernia, 0F RAINHIIIAIL, ENGLAND.

Specification of Letters mam.

Patented Mach 3, 1908,.

. Application filed In-oh '1. 1002.. Serialllo. 97.130.

To all whom it may concern; I

Be'it known that I, BALFOUR FRASER Mc- -TEi \R a subject of the King of E land and it the a=resident of Brook Cottage,'R county of Lancaster, England, have invented v new and useful: Improvements in Apparatus f for Drawing Hard-Metal Tubes, of which -In the following is a specification.

This invention has reference to the manufacture of hard metal tubes or hollow bodies, such as of steel, iron, copper, and'analogous or other hard metals; and more particularly to that part of the process of such manufacture wherein the tubes or tubular bodies are drawn through dies, generally, for reducing their diameter.

Further, the species of tubes or tubular bodies referred to is that which is without weld or seam;

According to this invention, the aperture of the die through which tubes are drawn,

and by which they are reduced, is of a va mg diameter at difi'erent'points along its aigis, it being bell-shaped or of analogous forform, or of an abrupt curved shape.

I The thickness of a die, according to this invention, for making tubes of medium or larger sizes is considerable; and the diameter of the apertureat the exit much smaller than the inlet end or mouth; and the effect is, that alarge reduction of diameter of tube can be made at each pass of the tube-through the die. Furthermore, the power necessary to draw the tube through'the die is not excessive; neither are the disruptive tendencies. Nor is the metal strained, or otherwise damaged.

In connection with the die above specified, a plug is employed within the tube, and within the planes of the faces of the die; and this f plu has a shape and contour similar to that of t e die aperture, or largely so. The

is is held in position-within the tube by a ar,

. ing dis osed and adjusted to the'position re .quired y means of this bar.

from one end, and is immovable therein,-be-

The end of the tube blank or tubular body tube is drawn through the die by a draw rod or bar, having upon it a head, which bears on the inner surface of the internal flange of the nozzle above referred to; and by the pull on the bar the tube is pulled through the die.

Insomecases, the surface of the die round the aperture is grooved or corrugated, there by.forming a p urality of rings or points of some cases the plug surface is of a similar formation or construction. When these points of contact are in the form of rings or annular-corrugations, the construction constitutes a series of dies, performing a series of successive diametrical reducing actions upon the tube as it passes through the apparatus.

, A further object and effect of' this ring or cor rugated construction of die, or die and plug, is that it serves a means by which lubricants can be. continuously supplied to the surface, or surfaces, of the tube, and the active surfaces of the die, or die and plug. The lubri cant may be introduced to the die, through suitable holes or openings from the outside; or the recesses or grooves of the die, or die and plug, may be filled with grease or like lubricant prior to the drawing action.

In the drawings illustrating my invention, Figures 1, 2, and 3 are longitudinal sectional elevations showing three modifications of apparatus or means for cold drawing tubes un- (lelfitlflis invention. 11' h -dr d I e err' enera y to t e awings, a esignates tlib ie holder or frame, which may be of any known suitable kind; e is the die fitting in the holder a; i is the plug for suporting the tube internally; and o is the tube.

he thickness of the die ewhich is for reducing tubes of medium or large size, say about from 8 to 18 inchesis made of considerable width, say about 6 inches, and the surface of the die ap'erture which acts upon the tube, is a tapering one, decreasing in diameter from the mouth or entrance face at e,

to the discharge face or end at 0 said surface support and pressure to the tube m series. i V

eter from the larger end i to the smaller end i and it is disposed within the die aperture. to be drawn is reduced by pressing or forging 50 Referring now to Fig. 1,-the die e is shown provided with two annular grooves or recesses f, by which, in the first place, the die is practically comprised of -three successive the surface of the tube and dies, as the tube larger sizes of tubes such as referred to, to be I made in a single pass or draw. Furthermore, by it, the metal is not subjected to abnormal or deteriorative stresses; and the power required in drawing isproportionately small; and it generally conduces to ood work, and obviates the straining or brea ing of the dies and machinery, and keeps the temperature of the parts down.

As an illustration of what may be done by the construction of this apparatus, comprising the form or construction of die and the internal holding up or supporting plug, and by means of lubricating the die and tube internally, and having a succession of diminishing lubricated die ortions or dies, as much as 6 inches diminutlon of diameter ina tube of 12 inch original diameter, can be effected in one pass; and similar roportional reductions can be effected in tu es of other diameters.

When the thickness of tubes as well as the diameter is to be reduced, the difference of diameter between the smaller end i of the plug 'i, and the internal diameter of the exit ende of the die, would be the same as the internal and external diameters of the tube required. The end portion 7? of the plug 11, is made cylindrical or parallel, as is also the discharge end portion near the face 6' of the die, and they together assist in guiding the tube out of the die in a right line, and in causing it to be drawn in a smooth and truly cylindrical form of even diameter. That is, while the other arts of the die guide and force the tube inwar s in a conical diminishing formation, the latter parallel arts change it from the conical or taperin fbrmation to the truly cylindrical, and gui e and direct it.

The lubricant or grease is introduced preferably into the annular recesses f, through holes 9, leading from the faces of the die to the back of the grooves; but if desired, they may be filled with grease from within the die aperture, prior to the tube being introduced.

The plug i will be held from the back end of the cold drawing bench or machine by the stem in the same way that such plugs .are usualfy held. As shown in Fig. 1, the plug i is provided with an annular recess or groove at k, and another recess is. *These rooves make the plug into one containing a p urality of su porting plugs or surfaces of successively smal er diameter, corresponding with the successive diminishing operative surfaces of the die e.

The leading end of the tube 0 is forged before-the drawing, into the form shown in the figure, that is, it is made in the form of a bell to correspond with the die aperture; and at its outer end the tube blank to be drawn, is

provided with a strong elon ated neck which is of smaller diameter t an the insi e diameter of the finished tube, (which is shown by the parallel .ortion 0); and the inner face of this interna ly projecting neck p forms a seat-to :receive the head 1" of the draw bar r, by means of which, the tube is pulled through the die; the inner face of this head 9 butting against the inner face of the neck p. 1 I

In some cases, instead of. the successive parts of the die 6 being in one piece, it may consist of a series of separate pieces or dies arranged in series, the diameters of their various a ertures varying, the first being the larger or argest, and the last the smaller or smallest. In the case of the apparatus or means set forth being re uired for reducing the thickness as 'well as t e diameter of the tube, the size of the mouth of the die 0, and the larger ortion 't of the plug i, would be so made t at the annular space between them would be larger at the commencement or mouth, and diminishing inwards, as shown in Fig. 2 and Fig. 3.

With regard to the mode of using the apparatus, and its operation, the tube would be placed in position in the die, as shown, the rod 1' passed through the opening in the neck p on the tube end, and the plug i placed in position in the tube 0 in the usual ordinary way; whereupon the tube will then be drawn through the die, and over the plug. By making the die broad, and with an extended operative surface of a gradually decreasing dlameter, biggest at the face of the entrance, and smallest at the face where the tube leaves the die; and by providing a plug/Z of decreasing diameter, adapted to support the tube internally during the greater portion of its passage between itself and the die surface; the tube is gradually reduced, and the crinkling or rucking of it, which would otherwise occur in attempting to make so large reductions as referred to, 1s prevented, and a smooth and well-finished surface is produced.

It also furnishes a means by which the metal is not strained or damaged, notwithstanding the great reduction effected in its diameter in a single pass, and the great pressure necessar to move it through the dies.

eferring to the modification in Fig. 2, the general form of die and parts are the same as those set forth with reference to and shown in Fig. l; but in this case, the operative sur face of the die e is continuous throughout, instead of consisting of a number of annular parts, there being no annular recesses for containing lubricating grease; and the annular space at the entrance or mouth of the die, 11. e. between the die aperture surface and the larger portion a" of the plug i, is larger within, and it tapers and diminishes in size, towards the dischargeend.

Referrin now to the modification shown in Fig. 3, this construction of parts, as regards the die e, and' the formation of the end of the tube 0, is similar to that shown in Fi 2, while the external form of the plu '1', 1s also similar; but in this case the tu e is forced through the die by the draw-in or forcing rod, which passes through a ho e in the lug 'i, and supports the lug, and presses on t e inner face of the neo p, similarly as the head 1* of the rod 1' does in the construction shown in Fig. 1, the rod 1' being pushed along by any suitable power, instead of being pulled. Otherwise than in these respects, this construction is the same as that shown in Fig. l. Having now described my invention, what I claim as new and desire to secure by Letters Patent is: v

1. An apparatus fordrawin hard metal tubes, comprising an external ie having an aperture therein which decreases in diameter from the mouth or entrance face to the disative surface tapering and decreasing in d1- ameter from the entrance end towards the discharge end and said discharge end portion being cylindrical and parallel with the cylindrical portion of the die and the said tapered op'eratlve surface being substantially straight.

2. An apparatus for drawinghard metal tubes, com risingan external die e having an a erture tlierein, the operative surface of W ich being a convex curve and decreasing in diameter from the entrance end to the discharge end and having a short c 'lindrical portion at its discharge end, annu ar chamersf in said operative surface, said die having ports therein leading to said chambers, a plug '11 disposed axially within the die a erture, said plug having its operative surface tapering and decreasin in diameter from the entrance end to the dlscharge end and said discharge end bein cylindrical and arallel with the cylindrical portion of the (he, said plug having annular recesses therein corresponding to the chambers in the surface of the die.

In witness whereof I have hereunto set my hand in presence of two witnesses.

BALFOUR FRASER MoTlEAR.

Witnesses:

SAM GooDALL, (3120. E. Gonnme. 

